Shoe sole



March 13, 1962 D. D. MCCARTHY SHOE SOLE Filed Jan. 12, 1960 United States Patent 3,024,790 SHOE SOLE Donald D. McCarthy, 7921 Springway Road, Ruxton, Md. Filed Jan. 12, 1960, Ser. No. 1,909 3 Claims. (Cl. 12S--589) This invention relates to shoe soles. A principal object of this invention is to provide an improved shoe sole and a shoe formed therewith for making walking easier. Another object is to improve foot comfort. A still further object is to provide a shoe sole which can, when attached to a shoe, minimize wrinkling and creasing in the shoe vamp.

The principal inventive feature of my invention is a continuously tapering sole beginning at a substantial thickness at a point behind the ball of the foot and tapering evenly down to a lesser thickness at the toe.

The objects and features of the invention will be more fully explained in conjunction with the accompanying drawings wherein:

FIG. 1 is a plan view of a sole adapted to be joined to an upper;

FIG. 2 is a side w'ew of the sole of FIG. 1;

FIG. 3 is an illustration of the shoe sole of FIG. 1 in use, and a skeleton view of a foot showing the relation of the metatarsus and phalange areas of the foot with the sole;

FIGS. 4 and 5 are sections of the sole taken on lines 4 and 5 of FIG. 3; and

FIG. 6 is a section of another preferred embodiment of the sole of the invention.

The sole may be formed, for instance, of crepe, cushion crepe, rubber, elastomer resin blend, composition, sport type compounds, leather or combinations thereof.

Referring to FIGS. 1-5 a molded sole has a forefoot portion having a maximum thickness at point 14, back of the ball, and tapers evenly down to a lesser sole thickness at the toe 18. To the rear of this forefoot portion is a back portion 10 with a thickness substantially less than that of the immediately adjacent forefoot portion. This decrease in thickness prevents transfer of inordinate loads directly to rear portions of the longitudinal arch area, and thus affords arch support with the prime load being taken by the metatarsal heads, and the forward portions of the metatarsals being supported as is orthopedically desirable. The back portion 10 continues evenly to the rear of the sole as a heel seat to which a heel extending somewhat below the bottom surface of the sole portion at 14 is joined. The top surface of the sole 22 is continuous, adapted to support a foot. As a specific example I have found that in utilizing cushion crepe rubber in a mans sole a thickness of 30 iron at the thickest point 14, behind the ball, taperingevenly to 15 iron at the toe is particularly desirable. In this embodiment the back portion including the heel seat has a thickness of 18 iron, and a 5 8" heel is joined thereto.

A preferred mans sole formed of non-cellular rubber material suited for stitched construction has a 9 iron toe, 24 iron behind the ball and a 12 iron back portion and heel seat.

Various iron thicknesses can be utilized to advantage, depending upon the material employed and the age-sex class of the wearer, adjusting for weight, appearance and flexibility, but the thickness relationship must be maintained substantially as disclosed.

It will be noted in FIG. 3 that the metatarsal 25 and phalanges 23, 24 are so positioned with respect to the sole that the metatarsophalangeal joint 21 and the metatarsal heads 16 are ahead of the thickest portion of the sole, and the taper extends evenly therefrom to the toe.

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In FIG. 6 there is illustrated a section of another preferred embodiment of the sole of this invention which is a combination sole comprised of a formed leather outsole portion 30 of generally even thickness throughout, and a specially molded forefoot pad 32. This pad is joined to the top surface of the forefoot portion of the sole which is so formed to receive it that the upper surface of the pad and the upper surface of the rear portion of the outsole together present a continuous surface for supporting a foot. The pad 32 is of a substantial thickness beginning behind the ball and tapers evenly to a point near the toe. The formed outsole conforming under the pad combines therewith to achieve a tapered composite sole functioning like the molded sole of FIGS. 1-5.

Another embodiment of the invention is a molded footwear, e.g., of plastic, rubber or canvas, with an upper integrally formed with a tapered sole as above.

A kinesiological study of walking reveals that as the forefoot portion of the forward foot begins to set down following, in time, the heel of that forward foot, the rear leg and foot is exerting, through the ball and toes, a relatively high and efficient propulsive force (and this force rapidly decreases as the human body moves forfard, with the muscles in the hind leg and foot losing efiiciency). Also at the moment when the forefoot portion of the forward foot begins to strike, the center of gravity of the human body is simultaneously swinging forward, but not yet over the metatarsal area of this forward foot. My invention takes advantage of the combination of this high and eflicient propulsive force and the momentum of the human body at this instant to slightly elevate the body in a smooth, orthopedically sound way.

According to the invention the thickest. portion of the tapered sole lies behind the metatarsal heads where the toes are joined to the longitudinal bones which form the longitudinal arch of the foot. This thickest sole portion generally registers with the downward curves of the forward portions of the metatarsals. Thus, the thickest part of the inclined plane is interposed between the walking foot and the ground just at the proper instant, and the human body is reaised by the heel and easily kept elevated by the sole, thus converting for an instant a part of the kinetic energy of the body and the propulsive work of the hind foot to potential energy.

As the body moves forward, and the ball of the foot rocks smoothly upon the inclined plane of the shoe sole the potential energy is transformed to useful work, helping the walker along. Accordingly, the less efficient, final propulsive forces of the hind leg and foot are not needed. Using this sole, a walker instinctively relaxes his hind leg and foot, when with prior art soles it. was necessary to continue pushing away for propulsion. The foot is, therefore, not flexed as much, and the shoe vamp is not creased and wrinkled because the hind foot does not have to flex to the final extreme positions necessary for the final stages of the push off previously necessary. Walking is easier and the feet are more comfortable. This can be achieved in a normal appearing sole which has no cleats or other mud-catching contours where desired.

It will be noted that foot load is spread evenly and no uncomfortbale localized high pressure zones occur.

I claim:

1. A shoe outsole of flexible material for use with a shoe upper and heel, the forepart of said sole, substantially across its entire width, having a maximum thickness at a point rearwardly of and adjacent to the metatarsal heads of the foot of the wearer and tapering continuously from at least the metatarsal heads of the foot of the wearer to the toe tip of the sole with the thickness at the toe tip being no more than substantially one half of the thickness of the sole at the metatarsal heads of the foot of the wearer so that the thickness of the sole interposed between the forepart of the foot of the wearer and the ground decreases from beneath the metatarsal heads forwardly to the toe tip and forming a rocker extending from said heads to said toe tip, Whereby when Walking occurs, the metatarsal heads of the wearers foot are elevated While they receive the wearers weight, and the foot thereafter rocks down against a progressively decreasing thickness of the sole.

2. A shoe sole according to claim 1 having a shank portion extending rearwa-rdly from said point which is rearwardly of and adjacent to the metatarsal heads of the foot, said portion being of a thickness substantially less than said maximum thickness.

3. A shoe sole according to claim 2 having a heel portion extending rearwardly of the shank providing a seat for attachment of the heel.

References Cited in the file of this patent UNITED STATES PATENTS 1,253,639 Smith Ian. 15, 1918 1,823,445 Goldstone Sept. 15, 1931 1,945,115 Legge Jan. 30, 1934 2,072,765 Oakley Mar. 2, 1937 2,111,666 Hubbard Mar. 22, 1938 2,307,032 Fisch Ian. 5, 1943 2,650,438 Whitman Sept. 1, 1953 FOREIGN PATENTS 461,028 Germany June 11, 1928 461,029 Germany June 11, 1928 860,322 Germany Dec. 18, 1952 

